Apparatus for separating particles and methods for using same

ABSTRACT

An apparatus suitable for separating particles and methods for using such apparatus are provided.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.61/352,989 filed Jun. 9, 2010.

FIELD OF THE INVENTION

The present invention relates to an apparatus suitable for separatingparticles and methods for using such apparatus. More particularly, thepresent invention relates to an apparatus that utilizes inertial and/oraerodynamic characteristic (for example drag) differences in particlesto separate particles into two or more groups.

BACKGROUND OF THE INVENTION

Apparatuses for conveying particles, such as pulp fibers are known inthe art. For example, there are numerous air-laying forming heads thatutilize pinwheels and/or screens and/or sieves through which all of theparticles traveling through the apparatuses pass. These knownapparatuses do not separate a portion of the particles from the otherparticles as the particles are traveling through the apparatuses. As canbe seen in FIGS. 1-4, the prior art apparatuses comprise multiplepinwheels and one or more screens or sieves, a single pinwheel and ascreen or sieve, multiple pinwheels without screens or sieves. None ofthese prior art apparatuses separate particles traveling through theapparatus into two or more distinct groups. In other words, none of theprior art apparatuses divert and/or remove only a portion of theparticles from the stream of particles traveling through apparatus,especially using inertial and/or aerodynamic characteristic differencesin the particles to cause the separation.

FIG. 5 is another prior art apparatus. At first glance, it would appearthat the apparatus would work to separate particles into two or moregroups. However, upon closer inspection and modeling, the apparatusfails to separate particles into two or more groups as they aretraveling through the apparatus. Particles passing through the apparatusdescribed in will hug the surface of the wall as shown in FIG. 5 andcontinue down along the walls of the S-curve. The rotor (paddle wheel)in the middle of the apparatus functions to provide additional axialmixing of the air and the particles (fibers) to provide a more uniformdistribution of the particles, not to separate the particles into two ormore groups, especially based on inertial and/or aerodynamiccharacteristic differences between the particles.

As a result of the designs of the prior art apparatuses, none of themteach or function to separate the particles traveling through them intotwo or more groups of particles, especially where the separation isbased on inertial and/or aerodynamic characteristic differences betweenthe particles traveling through the apparatuses.

Formulators desire a high-throughput apparatus that does not utilizescreens and/or sieves or have other obstructions in the main crossflow,while still being able to produce a more uniform distribution of theparticles, based on size, density, aspect ratio and other propertiesassociated with the particles.

Accordingly, there is a need for an apparatus that is capable ofseparating a portion of particles traveling through the apparatus fromother particles traveling through the apparatus and methods for usingsuch an apparatus.

SUMMARY OF THE INVENTION

The present invention fulfills the need described above by providing anapparatus capable of separating particles traveling through theapparatus into two or more groups and methods for using such apparatus.

In one example of the present invention, an apparatus for separatingparticles, the apparatus comprising a housing through which a pluralityof particles are capable of traveling and a separator component thatseparates the plurality of particles into two or more groups ofparticles as the plurality of particles travels through the apparatusduring operation of the apparatus, is provided.

In another example of the present invention, an apparatus for separatingparticles, wherein particles traveling through the apparatus areseparated into two or more groups based on inertial and/or aerodynamiccharacteristic differences between the particles, is provided.

In even another example of the present invention, an apparatus forseparating particles, the apparatus exhibits a ratio of Number ofAccepted Particles to Number of Trapped Particles of greater than 2 asmeasured according to the CFD Test Method described herein, is provided.

In yet another example of the present invention, an apparatus forseparating particles, the apparatus exhibits a ratio of Number ofAccepted Particles to Number of Trapped Particles of less than 0.5 asmeasured according to the CFD Test Method described herein, is provided.

In still another example of the present invention, a method for makingan article of manufacture, the method comprises the steps of:

a. providing an apparatus for separating particles;

b. supplying a plurality of particles to the apparatus such that theparticles are separated into two or more groups of particles as theparticles travel through the apparatus during operation of theapparatus;

c. collecting the particles that exit the apparatus on a collectiondevice to form an article of manufacture, is provided.

In yet another example of the present invention, an article ofmanufacture made by a method according to the present invention, isprovided.

In even still another example of the present invention, a method formaking a fibrous structure, the method comprises the steps of:

a. providing an apparatus for separating particles;

b. supplying a plurality of particles to the apparatus such that theparticles are separated into two or more groups of particles as theparticles travel through the apparatus during operation of theapparatus; and

c. mixing at least one of the two or more groups of particles with oneor more fibrous elements to form a fibrous structure; and

d. optionally, forming the fibrous structure on a belt, is provided.

In even still yet another example of the present invention, a fibrousstructure made by a method according to the present invention, isprovided.

Accordingly, the present invention provides and apparatus and methodsfor separating particles, articles of manufacture and fibrous structuresmade by using such apparatus, and methods for making articles ofmanufacture and/or fibrous structures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of a prior art apparatus through whichparticles travel;

FIG. 2 is a representation of another prior art apparatus through whichparticles travel;

FIG. 3 is a representation of yet another prior art apparatus throughwhich particles travel;

FIG. 4 is a representation of even yet another prior art apparatusthrough which particles travel;

FIG. 5 is a representation of still another prior art apparatus throughwhich particles travel;

FIG. 6 is a schematic, cross-sectional representation of one example ofan apparatus for separating particles according to the presentinvention;

FIG. 7 is a schematic, perspective representation of an example of apinwheel suitable for use in an apparatus according to the presentinvention;

FIG. 8A is a schematic front view representation of an example of apinwheel and fin arrangement suitable for use in an apparatus accordingto the present invention;

FIG. 8B is a schematic side view representation of pinwheel and finarrangement shown in FIG. 8A;

FIG. 9 is a schematic, cross-sectional representation of another exampleof an apparatus for separating particles according to the presentinvention;

FIG. 10 is a schematic representation of an example of a method formaking a fibrous structure according to the present invention;

FIG. 11A is an isometric representation of the void volume of anapparatus for separating particles according to the present invention;and

FIG. 11B is a side representation of the void volume of FIG. 11A.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

“Separator component” as used herein means a portion of an apparatus forseparating particles, which is capable of diverting a portion (less thanall) of the particles traveling through the apparatus such that thediverted particles are separated from the other particles that continueto travel through the apparatus. The separator component is that portionof the apparatus between an imaginary surface S₁ normal to the inlet ofthe apparatus and an imaginary surface S₂ normal to the outlet of theapparatus, as shown in FIG. 6. The angle at which the imaginary surfacesS₁ and S₂ intersect is angle α. The separator component may use inertialand/or aerodynamic characteristic differences between the particlestraveling through the apparatus to facilitate the separation of theparticles into two or more distinct groups.

The separator component may comprise an active component, such as arotating pinwheel that the diverted particles contact. The separatorcomponent may comprise a passive component such as a screen throughwhich the diverted particles pass. In one example, the separatorcomponent comprises both a rotating pinwheel and a screen. In anotherexample, the separator component comprises an opening within a wall ofthe housing of the apparatus through which a portion (less than all) ofthe particles pass as a result of the particles being separated from theother particles traveling through the apparatus. The opening may lead toa collector unit that stores the diverted particles and/or may lead to arecycling loop to inject the diverted particles, directly or indirectly,back into the apparatus. This feature of recycling may be applied to anyof the diverted/separated particles. For example, if the separatorcomponent comprises a rotating pinwheel, the particles diverted into therotating pinwheel may be reduced in size by the rotating pinwheel andthen be injected back into the particles that are traveling through theapparatus. In other words, the diverted particles may be temporarilyseparated from the other particles that continue to travel through theapparatus and may be reintroduced into the particles that are travelingthrough the apparatus once their characteristics, such as size, havebeen altered to be substantially similar to those particles that are notdiverted by the separator component.

The separator component may comprise a single mechanical device thatimparts mechanical energy to the particles.

In one example, the apparatus of the present invention may be void of ascreen and/or sieve.

The separator component is capable of separating particles travelingthrough the apparatus based on their inertial and/or aerodynamiccharacteristic differences. For example, particles with relatively highinertia and low drag will be separated by the separator component of theapparatus of the present invention from particles with relatively lowinertia and relatively high drag.

“Inertia” or “Inertial” as used herein means the tendency for a particleto continue moving in its current direction, irrespective of what thevelocity vectors of air are doing around it. As defined, a particle witha high inertia will continue along a straight line path through the bend(turn) at angle α of FIG. 6 and into the separator component. A particlewith low inertia will be more susceptible to the air velocity vectorsaround it and will more easily make the bend (turn) at angle α of FIG. 6and being diverted and/or separated from the other particles that arecontinuing to move through the apparatus to the outlet. It could bedescribed as a Force=Mass×Acceleration orForce=(Volume×Density)×Acceleration or Kinetic Energy=½(Mass)×(Velocity)or Kinetic Energy=½(Volume×Density)×(Velocity)² relationship. The massof the particle can be increased by increasing the density at a constantvolume, volume at a constant density (via particle size or aspect ratio)or by increasing volume and density.

“Aerodynamic characteristic” as used primarily means drag or solelymeans drag. Increasing the drag of a particle will make it moresusceptible to what the velocity vectors of air are doing to it. It isrelated to the specific surface area of the particle, which as the unitsof m²/g. Increasing the specific surface area of a particle either byincreasing the surface area at a given mass or constant surface area ata decreasing mass with both result in a particle being able to make thebend (turn) at angle α of FIG. 6 easier, since it will more closelyfollow the flow of air through the apparatus. Further, increasingdensity decreases specific surface area, increasing aspect ratiodecreases specific surface area, and decreasing particle size increasesspecific surface area.

“Fibrous structure” as used herein means a structure that comprises oneor more filaments and/or fibers. In one example, a fibrous structureaccording to the present invention means an orderly arrangement offilaments and/or fibers within a structure in order to perform afunction. Non-limiting examples of fibrous structures of the presentinvention include paper, fabrics (including woven, knitted, andnon-woven), and absorbent pads (for example for diapers or femininehygiene products).

Non-limiting examples of processes for making fibrous structures includeknown wet-laid papermaking processes and air-laid papermaking processes.Such processes typically include steps of preparing a fiber compositionin the form of a suspension in a medium, either wet, more specificallyaqueous medium, or dry, more specifically gaseous, i.e. with air asmedium. The aqueous medium used for wet-laid processes is oftentimesreferred to as a fiber slurry. The fibrous slurry is then used todeposit a plurality of fibers onto a forming wire or belt such that anembryonic fibrous structure is formed, after which drying and/or bondingthe fibers together results in a fibrous structure. Further processingthe fibrous structure may be carried out such that a finished fibrousstructure is formed. For example, in typical papermaking processes, thefinished fibrous structure is the fibrous structure that is wound on thereel at the end of papermaking, and may subsequently be converted into afinished product, e.g. a sanitary tissue product.

The fibrous structures of the present invention may be homogeneous ormay be layered. If layered, the fibrous structures may comprise at leasttwo and/or at least three and/or at least four and/or at least fivelayers.

The fibrous structures of the present invention may be co-formed fibrousstructures.

“Co-formed fibrous structure” as used herein means that the fibrousstructure comprises a mixture of at least two different materialswherein at least one of the materials comprises a filament, such as apolypropylene filament, and at least one other material, different fromthe first material, comprises a particle, such as a fiber and/or agranular substance and/or powder. In one example, a co-formed fibrousstructure comprises particles, such as fibers, such as wood pulp fibers,and filaments, such as polypropylene filaments.

“Particle” as used herein means a fiber, a granular substance and/or apowder.

“Aspect ratio” as used herein, with reference to a particle, especiallya fiber, means the diameter/length of the particle.

“Fibrous element” as used herein means a fiber and/or a filament.

“Fiber” and/or “Filament” as used herein means an elongate particlehaving an apparent length greatly exceeding its apparent width, i.e. alength to diameter ratio of at least about 10. For purposes of thepresent invention, a “fiber” is an elongate particle as described abovethat exhibits a length of less than 5.08 cm (2 in.) and a “filament” isan elongate particle as described above that exhibits a length ofgreater than or equal to 5.08 cm (2 in.).

Fibers are typically considered discontinuous in nature. Non-limitingexamples of fibers include pulp fibers such as wood pulp fibers andsynthetic staple fibers such as polyester fibers. The fibers may bemonocomponent or multicomponent, such as bicomponent fibers.

Filaments are typically considered continuous or substantiallycontinuous in nature. Filaments are relatively longer than fibers.Non-limiting examples of filaments include meltblown and/or spunbondfilaments. Non-limiting examples of materials that can be spun intofilaments include natural polymers, such as starch, starch derivatives,cellulose and cellulose derivatives, hemicellulose, hemicellulosederivatives, and synthetic polymers including, but not limited topolyvinyl alcohol filaments and/or polyvinyl alcohol derivativefilaments, and thermoplastic polymer filaments, such as polyesters,nylons, polyolefins such as polypropylene filaments, polyethylenefilaments, and biodegradable or compostable thermoplastic fibers such aspolylactic acid filaments, polyhydroxyalkanoate filaments andpolycaprolactone filaments. The filaments may be monocomponent ormulticomponent, such as bicomponent filaments.

In one example of the present invention, “fiber” refers to papermakingfibers. Papermaking fibers useful in the present invention includecellulosic fibers commonly known as wood pulp fibers. Applicable woodpulps include chemical pulps, such as Kraft, sulfite, soda, and sulfatepulps, as well as mechanical pulps including, for example, groundwood,thermomechanical pulp and chemically modified thermomechanical pulp.Chemical pulps, however, may be preferred since they impart a superiortactile sense of softness to tissue sheets made therefrom. Pulps derivedfrom both deciduous trees (hereinafter, also referred to as “hardwood”)and coniferous trees (hereinafter, also referred to as “softwood”) maybe utilized. The hardwood and softwood fibers can be blended, oralternatively, can be deposited in layers to provide a stratified web.U.S. Pat. Nos. 4,300,981 and 3,994,771 are incorporated herein byreference for the purpose of disclosing layering of hardwood andsoftwood fibers. Also applicable to the present invention are fibersderived from recycled paper, which may contain any or all of the abovecategories as well as other non-fibrous materials such as fillers andadhesives used to facilitate the original papermaking.

In addition to the various wood pulp fibers, other cellulosic fiberssuch as cotton linters, rayon, lyocell and bagasse can be used in thisinvention. Other sources of cellulose in the form of fibers or capableof being spun into fibers include grasses and grain sources.

“Sanitary tissue product” as used herein means a soft, low density (i.e.<about 0.15 g/cm3) web useful as a wiping implement for post-urinary andpost-bowel movement cleaning (toilet tissue), for otorhinolaryngologicaldischarges (facial tissue), and multi-functional absorbent and cleaninguses (absorbent towels). The sanitary tissue product may be convolutedlywound upon itself about a core or without a core to form a sanitarytissue product roll.

In one example, the sanitary tissue product of the present inventioncomprises a fibrous structure according to the present invention.

The sanitary tissue products of the present invention may exhibit abasis weight between about 10 g/m² to about 120 g/m² and/or from about15 g/m² to about 110 g/m² and/or from about 20 g/m² to about 100 g/m²and/or from about 30 to 90 g/m². In addition, the sanitary tissueproduct of the present invention may exhibit a basis weight betweenabout 40 g/m² to about 120 g/m² and/or from about 50 g/m² to about 110g/m² and/or from about 55 g/m² to about 105 g/m² and/or from about 60 to100 g/m².

The sanitary tissue products of the present invention may be in the formof sanitary tissue product rolls. Such sanitary tissue product rolls maycomprise a plurality of connected, but perforated sheets of fibrousstructure, that are separably dispensable from adjacent sheets. In oneexample, one or more ends of the roll of sanitary tissue product maycomprise an adhesive and/or dry strength agent to mitigate the loss offibers, especially wood pulp fibers from the ends of the roll ofsanitary tissue product.

The sanitary tissue products of the present invention may comprisesadditives such as softening agents, temporary wet strength agents,permanent wet strength agents, bulk softening agents, lotions,silicones, wetting agents, latexes, especially surface-pattern-appliedlatexes, dry strength agents such as carboxymethylcellulose and starch,and other types of additives suitable for inclusion in and/or onsanitary tissue products.

“Weight average molecular weight” as used herein means the weightaverage molecular weight as determined using gel permeationchromatography according to the protocol found in Colloids and SurfacesA. Physico Chemical & Engineering Aspects, Vol. 162, 2000, pg. 107-121.

“Basis Weight” as used herein is the weight per unit area of a samplereported in lbs/3000 ft² or g/m².

“Machine Direction” or “MD” as used herein means the direction parallelto the flow of the fibrous structure through the fibrous structuremaking machine and/or sanitary tissue product manufacturing equipment.

“Cross Machine Direction” or “CD” as used herein means the directionparallel to the width of the fibrous structure making machine and/orsanitary tissue product manufacturing equipment and perpendicular to themachine direction.

“Ply” as used herein means an individual, integral fibrous structure.

“Plies” as used herein means two or more individual, integral fibrousstructures disposed in a substantially contiguous, face-to-facerelationship with one another, forming a multi-ply fibrous structureand/or multi-ply sanitary tissue product. It is also contemplated thatan individual, integral fibrous structure can effectively form amulti-ply fibrous structure, for example, by being folded on itself.

As used herein, the articles “a” and “an” when used herein, for example,“an anionic surfactant” or “a fiber” is understood to mean one or moreof the material that is claimed or described.

All percentages and ratios are calculated by weight unless otherwiseindicated. All percentages and ratios are calculated based on the totalcomposition unless otherwise indicated.

Unless otherwise noted, all component or composition levels are inreference to the active level of that component or composition, and areexclusive of impurities, for example, residual solvents or by-products,which may be present in commercially available sources.

Apparatus For Separating Particles

In one example of the present invention, an apparatus for separatingparticles comprises a housing through which a plurality of particles arecapable of traveling and a separator component through which only aportion of the particles travel during operation of the apparatus.

FIG. 6 shows an apparatus for separating particles 10 a in accordancewith the present invention. The apparatus 10 a is suitable forseparating particles, for example particles 12 a and particles 12 b,which exhibit different inertial and/or aerodynamic characteristicdifferences. In the present example, the particles 12 b may beaggregates of the particles 12 a. At least a portion of the particles 12b are separated from the other particles; namely, particles 12 a, by aseparator component 14. This separation of particles may be evidenced byan increased concentration of a certain particle within one group and anincreased concentration of another particle in the other group. Forexample, as some of the particles 12 b are separated from the group ofparticles 12 a and 12 b that enter the apparatus 10 a, the group ofparticles from which the particles 12 b are separated exhibits anincreased concentration of particles 12 a and the group of particlesthat is formed by the diverted and/or separated particles 12 b exhibitsan increased concentration of particles 12 b. In other words, theparticles 12 b preferentially are removed from the group of particles 12a and 12 b that enter the apparatus 10 a even though some of theparticles 12 a may be separated, along with the particles 12 b and/orsome of the particles 12 b may remain with the particles 12 a of theoriginal group of particles 12 a and 12 b that entered the apparatus 10a. The particles 12 b may exhibit different inertial and/or aerodynamiccharacteristic differences than the particles 12 a.

The separator component 14 of the apparatus 10 a may comprise amacerator, such as a pinwheel 16 as shown in detail in FIG. 7. In oneexample, the pinwheel 16 is a rotating pinwheel. For example, thepinwheel may rotate at a speed of at least 1000 rpm during operation ofthe apparatus 10 a. In one example, the separator component 14 comprisesa portion of the housing 18 of the apparatus. In addition to thepinwheel 16, the separator component 14 may further comprise fins 17,such as stationary fins extending from the housing 18 that help todirect the diverted and/or separated particles, for example particles 12b, into the pinwheel 16. In addition to the fins 17, the separatorcomponent 14 may also comprise a source of fluid 19, such as compressedair, that ensures that diverted and/or separated particles, for exampleparticles 12 b contact the pinwheel 16. The apparatus 10 a is designedsuch that a portion of the group of particles 12 a and 12 b, for exampleparticles 12 b, are diverted by the separator component 14 such thatthey are separated from the other particles within the group, forexample particles 12 a, which continue to travel unfettered through theapparatus 10 a.

In addition to the separator component 14, the apparatus 10 a furthercomprises a housing 18 that defines an interior void volume 20 throughwhich the particles 12 a, 12 b, at least partially travel along aparticle flow path as represented by the arrows in FIG. 6. The housing18 comprises a particle inlet 22 through which the group of particles 12a and 12 b are introduced into the apparatus 10 a. The particle inlet 22is positioned upstream of the separator component 14. The housing 18also comprises a particle outlet 24 through which the particles thathave not been diverted and/or separated; namely, the group of particlesexhibiting a higher concentration of particles 12 a (since the particles12 b have been preferentially diverted and/or separated from group ofparticles 12 a and 12 b that were introduced into the apparatus) exitthe apparatus 10 a. The particle outlet 24 is positioned downstream ofthe separator component 14. A plurality of particles 12 a and 12 b enterthe apparatus 10 a through the particle inlet 22 and exit the apparatus10 a through the particle outlet 24. In one example, particles 12 bcomprise aggregates of particles 12 a, which after being separated fromthe other particles 12 a are altered, such as the aggregates are brokeninto individual particles 12 a and may be reintroduced into the group ofparticles 12 a that are traveling through the apparatus 10 a to theparticle outlet 24.

The interior void volume 20 defined by the housing 18 of the apparatus10 a between the particle inlet 22 and the particle outlet 24 comprisesan angle α, formed by intersecting imaginary surfaces normal to theparticle inlet 22 and particle outlet 24, of greater than 20° and lessthan 160° and/or greater than 45° and less than 110°. In one example,particles 12 a travel within the interior void volume 20 from theparticle inlet 22 through the angle α to the particle outlet 24 suchthat they are not diverted and/or separated from the group of particles12 a and 12 b by the separator component 14. In one example, particles12 b travel within the interior void volume 20 from the particle inlet22 and are diverted and/or separated from the group of particles 12 aand 12 b by the separator component 14. Particles 12 b may bereintroduced into the stream of particles that have not been divertedand/or separated by the separator component 14, which continue to travelthrough the apparatus 10 a to the particle outlet 24.

As shown in FIG. 7, the pinwheel 16 comprises a shaft 26 about which thepinwheel 16 rotates.

FIGS. 8A and 8B illustrate an example of a pinwheel 16 and fin 17arrangement suitable for use in the apparatus 10 a of FIG. 6.

FIG. 9 illustrates another example of an apparatus for separatingparticles 10 b of the present invention. The apparatus 10 b is suitablefor separating particles, for example particles 12 a and particles 12 b,which exhibit different inertial and/or aerodynamic characteristicdifferences. In the present example, the particles 12 b may beaggregates of the particles 12 a. At least a portion of the particles 12b are separated from the other particles; namely, particles 12 a, by aseparator component 14. This separation of particles may be evidenced byan increased concentration of a certain particle within one group and anincreased concentration of another particle in the other group. Forexample, as some of the particles 12 b are separated from the group ofparticles 12 a and 12 b that enter the apparatus 10 b, the group ofparticles 12 a and 12 b from which the particles 12 b are separatedexhibits an increased concentration of particles 12 a and the group ofparticles that is formed by the diverted and/or separated particles 12 bexhibits an increased concentration of particles 12 b. In other words,the particles 12 b preferentially are removed from the group ofparticles 12 a and 12 b that enter the apparatus 10 b even though someof the particles 12 a may be separated, along with the particles 12 band/or some of the particles 12 b may remain with the particles 12 a ofthe original group of particles 12 a and 12 b that entered the apparatus10 b. The particles 12 b may exhibit different inertial and/oraerodynamic characteristic differences than the particles 12 a.

The separator component 14 of the apparatus 10 b may comprise an opening28 within the housing 18 through which a portion of the group ofparticles 12 a and 12 b, for example particles 12 b, pass and are thusseparated from the other particles, for example particles 12 a. Theopening 28 may be connected to a collecting device (not shown). Theapparatus 10 b is designed such that a portion of the group of particles12 a and 12 b, for example particles 12 b, are diverted by the separatorcomponent 14 such that they are separated from the other particleswithin the group; for example particles 12 a, which continue to travelunfettered through the apparatus 10 b.

In addition to the separator component 14, the apparatus 10 b furthercomprises a housing 18 that defines an interior void volume 20 throughwhich the particles 12 a, 12 b, at least partially travel along aparticle flow path as represented by the arrows in FIG. 9. The housing18 comprises a particle inlet 22 through which the group of particles 12a and 12 b are introduced into the apparatus 10 a. The particle inlet 22is positioned upstream of the separator component 14. The housing 18also comprises a particle outlet 24 through which the particles thathave not been diverted and/or separated; namely, the group of particlesexhibiting a higher concentration of particles 12 a (since the particles12 b have been preferentially diverted and/or separated from group ofparticles 12 a and 12 b that were introduced into the apparatus) exitthe apparatus 10 b. The particle outlet 24 is positioned downstream ofthe separator component 14. A plurality of particles 12 a and 12 b enterthe apparatus 10 b through the particle inlet 22 and exit the apparatus10 b through the particle outlet 24. In one example, particles 12 bcomprise aggregates of particles 12 a, which after being separated fromthe other particles 12 a are altered, such as the aggregates are brokeninto individual particles 12 a and may be reintroduced into the group ofparticles 12 a that are traveling through the apparatus 10 b to theparticle outlet 24.

The interior void volume 20 defined by the housing 18 of the apparatus10 b between the particle inlet 22 and the particle outlet 24 comprisesan angle α, formed by intersecting imaginary surfaces normal to theparticle inlet 22 and particle outlet 24, of greater than 20° and lessthan 160° and/or greater than 45° and less than 110°. In one example,particles 12 a travel within the interior void volume 20 from theparticle inlet 22 through the angle α to the particle outlet 24 suchthat they are not diverted and/or separated from the group of particles12 a and 12 b by the separator component 14. In one example, particles12 b travel within the interior void volume 20 from the particle inlet22 and are diverted and/or separated from the group of particles 12 aand 12 b by the separator component 14. Particles 12 b may bereintroduced into the stream of particles that have not been divertedand/or separated by the separator component 14, which continue to travelthrough the apparatus 10 a to the particle outlet 24.

Even though the above description has exemplified particles 12 b asbeing aggregates of particles 12 a, different particles (different insize, different in composition) may be separated by passing theparticles through an apparatus according to the present invention.

In another example of the present invention, an apparatus for separatingparticles utilizes inertial and/or aerodynamic characteristicdifferences between the particles traveling through the apparatus tospatially separate the particles into two or more groups based on theirinertia. The particles of at least one of the two or more groups ofparticles formed will then be treated differently than particles of atleast one of the other two or more groups of particles. The apparatusmay be designed as described herein.

In another example of the present invention, an apparatus for separatingparticles exhibits a ratio of Number of Accepted Particles to Number ofTrapped Particles of greater than 2 and/or greater than 3 and/or greaterthan 4 and/or greater than 5 and/or less than 0.5 and/or less than 0.3and/or less than 0.25 and/or less than 0.2 and/or less than 0.05 asmeasured according to the CFD Test Method described herein at anycondition set forth in the test method. The apparatus may be designed asdescribed herein. The apparatus is designed to separate particles basedon the particles' inertial and/or aerodynamic characteristicdifferences.

Table 1 below sets for a range of ratios of Number of Accepted Particlesto Number of Trapped Particles at a given density (22, 86, and 150kg/m³), a given size (0.001, 0.0045, and 0.008 m), and a given aspectratio (0.01, 0.4, 0.8, and 1.0).

TABLE 1 #Accepted Size Aspect Density #Trapped (m) Ratio (kg/m³ 9.170.001 0.01 22 4.25 0.0045 0.01 22 3.02 0.008 0.01 22 1.21 0.001 0.4 220.10 0.0045 0.4 22 0.01 0.008 0.4 22 0.11 0.001 0.8 22 0.01 0.0045 0.822 0.06 0.008 0.8 22 0.01 0.001 1.0 22 0.36 0.0045 1.0 22 0.21 0.008 1.022 4.74 0.001 0.01 86 1.58 0.0045 0.01 86 0.90 0.008 0.01 86 0.13 0.0010.4 86 0.00 0.0045 0.4 86 0.06 0.008 0.4 86 0.00 0.001 0.8 86 0.230.0045 0.8 86 0.13 0.008 0.8 86 0.19 0.001 1.0 86 0.14 0.0045 1.0 860.13 0.008 1.0 86 3.18 0.001 0.01 150 0.92 0.0045 0.01 150 0.45 0.0080.01 150 0.01 0.001 0.4 150 0.06 0.0045 0.4 150 0.33 0.008 0.4 150 0.040.001 0.8 150 0.12 0.0045 0.8 150 0.13 0.008 0.8 150 0.18 0.001 1.0 1500.12 0.0045 1.0 150 0.13 0.008 1.0 150

The particles traveling through the apparatus of the present inventionmay exhibit a density of 150 kg/m³ or less and/or 86 kg/m³ or lessand/or 22 kg/m³ or less. The particles may exhibit an aspect ratio of1.0 or less and/or 0.8 or less and/or 0.4 or less and/or 0.01 or less.The particles may exhibit a size of 0.008 m or less and/or 0.0045 m orless and/or 0.001 or less.

The apparatus for separating particles of the present invention and/orcomponents thereof may be made from any suitable material known in theart. Non-limiting examples of suitable materials include aluminum,steel, stainless steel, brass, bronze, polycarbonate and mixturesthereof.

Method For Separating Particles

In one example of the present invention, a method for separating aplurality of particles according to the present invention comprisessteps of:

a. providing an apparatus for separating particles according to thepresent invention, and

b. supplying a plurality of particles to the apparatus such that theparticles are separated into two or more groups of particles as theparticles travel through the apparatus during operation of theapparatus.

The apparatus may separate the particles by the inertial and/oraerodynamic characteristic differences between the particles.

In one example, the apparatus for separating particles comprises ahousing through which a plurality of particles are capable of travelingand a separator component that is capable of separating the particlesinto two or more groups during operation.

In one example, the plurality of particles are supplied to the apparatusby a solid particle discretizer, such as a hammer mill.

The particles may exhibit a density of less than 500 kg/m³ and/or lessthan 300 kg/m³ and/or 150 kg/m³ or less and/or 86 kg/m³ or less and/or22 kg/m³ or less.

The particles may exhibit a size of 0.0254 m or less and/or 0.008 m orless and/or 0.0045 m or less and/or 0.001 m or less.

The particles may exhibit an aspect ratio (diameter/length) of 1.0 orless and/or 0.8 or less and/or 0.4 or less and/or 0.01 or less.

Method For Making an Article of Manufacture

In one example of the present invention, a method for making an articleof manufacture, comprises the steps of:

a. providing an apparatus for separating particles according to thepresent invention;

b. supplying a plurality of particles to the apparatus such that theparticles are separated into two or more groups of particles as theparticles travel through the apparatus during operation of theapparatus; and

c. mixing at least one of the two or more groups of particles with oneor more fibrous elements to form an article of manufacture; and

d. optionally, forming the article of manufacture on a belt, such as apatterned belt.

In one example, the step of mixing comprises collecting the particlesand fibrous elements on a collection device, such as a belt, for examplea patterned belt.

In one example, the particles comprise pulp fibers. In another example,the fibrous elements comprise filaments, such as polypropylenefilaments.

The article of manufacture may be a fibrous structure.

In another example of the present invention, a method for making afibrous structure comprises the steps of:

a. providing an apparatus for separating particles according to thepresent invention;

b. supplying a plurality of particles to the apparatus such that theparticles are separated into two or more groups of particles as theparticles travel through the apparatus during operation of theapparatus;

c. combining the particles that exit the apparatus with a plurality offilaments, such as meltblown filaments; and

d. collecting the combination of particles and filaments on a collectiondevice to form a fibrous structure.

In one example, the step of combining the particles with the filamentshappens in space prior to being collected on the collection device.

The particles may comprise pulp fibers and the filaments may comprisemeltblown polypropylene filaments.

Non-limiting Example of Method For Making A Fibrous Structure

A non-limiting example of a method/process for making a fibrousstructure according to the present invention is represented in FIG. 10.The process shown in FIG. 10 comprises the step of mixing a plurality ofparticles 12 a, 12 b, such as fibers, with a plurality of filaments 30.In one example, the particles 12 a, 12 b, are wood pulp fibers, such asSSK fibers and/or Eucalyptus fibers, and the filaments 30 arepolypropylene filaments. The particles 12 a, 12 b, may be combined withthe filaments 30, such as by being delivered to a stream of filaments 30from a hammer mill 32 via an apparatus for separating particles 10 aaccording to the present invention to form a mixture of filaments 30 andparticles 12 a, 12 b, (preferentially particles 12 a). The filaments 30may be created by meltblowing from a meltblown die 34. The mixture ofparticles 12 a, 12 b, and filaments 30 are collected on a collectiondevice, such as a belt 36 to form a fibrous structure 38. The collectiondevice may be a patterned and/or molded belt that results in the fibrousstructure exhibiting a surface pattern, such as a non-random, repeatingpattern. The molded belt may have a three-dimensional pattern on it thatgets imparted to the fibrous structure 38 during the process.

In one example of the present invention, the fibrous structures are madeusing a die comprising at least one filament-forming hole, and/or 2 ormore and/or 3 or more rows of filament-forming holes from whichfilaments are spun. At least one row of holes contains 2 or more and/or3 or more and/or 10 or more filament-forming holes. In addition to thefilament-forming holes, the die comprises fluid-releasing holes, such asgas-releasing holes, in one example air-releasing holes, that provideattenuation to the filaments formed from the filament-forming holes. Oneor more fluid-releasing holes may be associated with a filament-forminghole such that the fluid exiting the fluid-releasing hole is parallel orsubstantially parallel (rather than angled like a knife-edge die) to anexterior surface of a filament exiting the filament-forming hole. In oneexample, the fluid exiting the fluid-releasing hole contacts theexterior surface of a filament formed from a filament-forming hole at anangle of less than 30° and/or less than 20° and/or less than 10° and/orless than 5° and/or about 0°. One or more fluid releasing holes may bearranged around a filament-forming hole. In one example, one or morefluid-releasing holes are associated with a single filament-forming holesuch that the fluid exiting the one or more fluid releasing holescontacts the exterior surface of a single filament formed from thesingle filament-forming hole. In one example, the fluid-releasing holepermits a fluid, such as a gas, for example air, to contact the exteriorsurface of a filament formed from a filament-forming hole rather thancontacting an inner surface of a filament, such as what happens when ahollow filament is formed.

After the fibrous structure 38 has been formed on the collection device,the fibrous structure 38 may be subjected to post-processing operationssuch as embossing, thermal bonding, tuft-generating operations,moisture-imparting operations, and surface treating operations to form afinished fibrous structure. One example of a surface treating operationthat the fibrous structure may be subjected to is the surfaceapplication of an elastomeric binder, such as ethylene vinyl acetate(EVA), latexes, and other elastomeric binders. Such an elastomericbinder may aid in reducing the lint created from the fibrous structureduring use by consumers. The elastomeric binder may be applied to one ormore surfaces of the fibrous structure in a pattern, especially anon-random repeating pattern, or in a manner that covers orsubstantially covers the entire surface(s) of the fibrous structure.

In one example, the fibrous structure 38 and/or the finished fibrousstructure may be combined with one or more other fibrous structures. Forexample, another fibrous structure, such as a filament-containingfibrous structure, such as a polypropylene filament fibrous structuremay be associated with a surface of the fibrous structure 38 and/or thefinished fibrous structure. The polypropylene filament fibrous structuremay be formed by meltblowing polypropylene filaments (filaments thatcomprise a second polymer that may be the same or different from thepolymer of the filaments in the fibrous structure 38) onto a surface ofthe fibrous structure 38 and/or finished fibrous structure. In anotherexample, the polypropylene filament fibrous structure may be formed bymeltblowing filaments comprising a second polymer that may be the sameor different from the polymer of the filaments in the fibrous structure38 onto a collection device to form the polypropylene filament fibrousstructure. The polypropylene filament fibrous structure may then becombined with the fibrous structure 38 or the finished fibrous structureto make a two-ply fibrous structure—three-ply if the fibrous structure38 or the finished fibrous structure is positioned between two plies ofthe polypropylene filament fibrous structure. The polypropylene filamentfibrous structure may be thermally bonded to the fibrous structure 38 orthe finished fibrous structure via a thermal bonding operation.

The process for making fibrous structure 38 may be close coupled (wherethe fibrous structure is convolutedly wound into a roll prior toproceeding to a converting operation) or directly coupled (where thefibrous structure is not convolutedly wound into a roll prior toproceeding to a converting operation) with a converting operation toemboss, print, deform, surface treat, or other post-forming operationknown to those in the art. For purposes of the present invention, directcoupling means that the fibrous structure 38 can proceed directly into aconverting operation rather than, for example, being convolutedly woundinto a roll and then unwound to proceed through a converting operation.

Test Methods

A. Computational Fluid Dynamics (CFD) Test Method

Computational fluid dynamics (CFD) is used to assess the destination ofparticles within an apparatus for separating particles. Fluent 12.1.4software commercially available from ANSYS, Inc. of Ann Arbor, Mich. isused for the CFD modeling. The model inputs of Table 2 are used in theFluent 12.1.4 software:

TABLE 2 Model Settings Space 3D Time Steady Viscous Reynolds StressModel Wall Treatment Standard Wall Functions RSM Wall Reflection EffectsOption Enabled RSM Wall B.C. Option (solve k) Enabled QuadraticPressure-Strain Option Disabled Heat Transfer Enabled Solidification andMelting Disabled Radiation None Species Transport Disabled CoupledDispersed Phase Disabled Pollutants Disabled Soot Disabled

The material properties used for the Fluent 12.1.4 CFD modeling areincompressible ideal gas for the motive fluid of air, and the particlediameter, density, and aspect ratios are varied in accordance with Table3.

TABLE 3 Particle Characteristic Values Aspect Ratio (diameter/length)0.01, 0.4, 0.8, 1.0 Density (kg/m³) 22, 86, 150 Size (m) 0.001, 0.0045,0.008

Additional information for the air fluid characteristics for the Fluent12.1.4 CFD modeling are set forth in Table 4.

TABLE 4 Property Units Method Value(s) Density kg/m³ incompressible-Variable ideal-gas Cp (Specific Heat) j/kg-k constant 1006.43 ThermalConductivity w/m-k constant 0.0242 Viscosity kg/m-s constant 1.7894001 ×10⁻⁵ Molecular Weight kg/kgmol constant 28.966 Thermal Expansion 1/kconstant 0 Coefficient Speed of Sound m/s none Variable

The majority of wall space, which forms the boundaries of the voidvolume of an apparatus for separating particles that is being assessedby the Fluent 12.1.4 CFD modeling that do not have flow moving in or outof them, are assumed to be of aluminum composition. The particles usedin the Fluent 12.1.4 CFD modeling are assumed to have a normalrestitution coefficient of 0.3, a tangent restitution coefficient of0.3, and a reflect boundary condition for the particles. The wallsurfaces near the separator component of the apparatus for separatingparticles have the same characteristics as the other walls except thatthese surfaces have a “trap” boundary condition, such that if a particlehits these wall surfaces it will stop moving though the domain.

The inlet boundary condition can either be mass flow specified orvelocity specified so long as they are representative of the flowsexpected to move through the apparatus for separating particles beingassessed. The particle injection occurs at the inlet boundary conditionas a surface injection. Particle characteristics for the injections areshown in Table 3 above. The aspect ratios of the particles are definedin the discrete model. Exit boundary conditions are specified atpressure outlet.

Energy, Reynolds Stress, Flow, and Turbulence equations are solved to aresidual of 1×10⁻³ or smaller if steady state flow exists, otherwise anon-steady state analysis should be performed with time incrementssufficiently small to achieve the above residuals. The simple scheme ofpressure-velocity coupling is used.

To assess an apparatus for separating particles according to this CFDTest Method, Gambit software commercially available from ANSYS, Inc. ofAnn Arbor, Mich. or another suitable geometry program is used to inputthe interior, void volume (void space through which particles flowduring operation) of the apparatus for separating particles. Wallsurfaces of the apparatus for separating particles whose only intent isto contain the flow are treated by the particles as a reflectionboundary condition, while those intended to macerate and/or otherwiseimpart mechanical energy for the intent of further particle sizereduction, or for the purpose of sieving or screening particles wouldhave a trap boundary condition for the particles. If the apparatus oneor more additional exits, for further treatment of the separatedparticles, then the additional exit has a trap boundary condition forthe particles. Injections of particles are then introduced into the voidvolume at the inlet boundary condition as a surface injection, andallowed to pass through the void volume. At the end of the particleinjection sequence, a summary report is created that describes thenumber of particles that are trapped in the void volume (“Number ofTrapped Particles”) and the number of particles that escape the voidvolume (“Number of Accepted Particles”).

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An apparatus for separating particles, theapparatus comprising a housing through which a plurality of particlesare capable of traveling, a separator component that separates theplurality of particles into two or more groups of particles, and amacerator associated with the apparatus such that after separation bythe separator component one of the two or more groups of particles doesnot contact the macerator during operation of the apparatus; wherein theother of the two or more groups of particles is reintroduced into thegroup of particles that does not contact the macerator.
 2. The apparatusaccording to claim 1 wherein the separator component comprises apinwheel.
 3. The apparatus according to claim 1 wherein the separatorcomponent comprises an opening in the housing through which theseparated group of particles passes.
 4. The apparatus according to claim1 wherein the housing comprises a particle inlet upstream of theseparator component and a particle outlet downstream of the separatorcomponent, wherein the plurality of particles enter the housing throughthe particle inlet and exit the housing through the particle outlet. 5.The apparatus according to claim 1 wherein the housing defines aninterior void volume comprising an angle α formed by intersectingimaginary surfaces normal to the particle inlet and particle outlet ofgreater than 20° and less than 160°.
 6. The apparatus according to claim5 wherein the angle α is greater than 45° and less than 110°.
 7. Theapparatus according to claim 1 wherein the particles are selected fromthe group consisting of: fibers, granular substances, powders andmixtures thereof.
 8. The apparatus according to claim 1 wherein theparticles comprise fibers.
 9. The apparatus according to claim 8 whereinthe fibers comprise pulp fibers.